In this study, a bioremediation approach was evaluated for the decontamination of an aquifer affected by the release of organohalides by an industrial landfill. After preliminary physicochemical and microbiological characterization of the landfill groundwater, the stimulation of natural organohalide respiration by the addition of a reducing substrate (i.e. molasse) was tested both at microcosms and at field scales, by the placement of an anaerobic permeable reactive bio-barrier. Illumina sequencing of cDNA 16S rRNA gene revealed that organohalide-respiring bacteria of genera Geobacter, Sulforospirillum, Dehalococcoides, Clostridium and Shewanella were present within the aquifer microbial community, along with fermentative Firmicutes and Parvarchaeota. Microcosm experiments confirmed the presence of an active natural attenuation, which was boosted by the addition of the reducing substrate. Field tests showed that the bio-barrier decreased the concentration of chloroethenes at a rate of 23.74 kg d-1. Monitoring of organohalide respiration biomarkers by qPCR and Illumina sequencing revealed that native microbial populations were involved in the dechlorination process, although their specific role still needs to be clarified. The accumulation of lower-chloroethenes suggested the need the future improvement of the present approach by supporting bacterial vinyl-chloride oxidation, to achieve a complete degradation of chloroethenes.

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community / M. Bertolini, S. Zecchin, G.P. Beretta, P. De Nisi, L. Ferarri, L. Cavalca. - In: WATER. - ISSN 2073-4441. - 13:17(2021 Sep 05), pp. 2442.1-2442.22. [10.3390/w13172442]

Effectiveness of Permeable Reactive Bio-Barriers for Bioremediation of an Organohalide-Polluted Aquifer by Natural-Occurring Microbial Community

M. Bertolini
Primo
Writing – Original Draft Preparation
;
S. Zecchin
Secondo
Writing – Review & Editing
;
G.P. Beretta
Membro del Collaboration Group
;
P. De Nisi
Methodology
;
L. Cavalca
Ultimo
Supervision
2021

Abstract

In this study, a bioremediation approach was evaluated for the decontamination of an aquifer affected by the release of organohalides by an industrial landfill. After preliminary physicochemical and microbiological characterization of the landfill groundwater, the stimulation of natural organohalide respiration by the addition of a reducing substrate (i.e. molasse) was tested both at microcosms and at field scales, by the placement of an anaerobic permeable reactive bio-barrier. Illumina sequencing of cDNA 16S rRNA gene revealed that organohalide-respiring bacteria of genera Geobacter, Sulforospirillum, Dehalococcoides, Clostridium and Shewanella were present within the aquifer microbial community, along with fermentative Firmicutes and Parvarchaeota. Microcosm experiments confirmed the presence of an active natural attenuation, which was boosted by the addition of the reducing substrate. Field tests showed that the bio-barrier decreased the concentration of chloroethenes at a rate of 23.74 kg d-1. Monitoring of organohalide respiration biomarkers by qPCR and Illumina sequencing revealed that native microbial populations were involved in the dechlorination process, although their specific role still needs to be clarified. The accumulation of lower-chloroethenes suggested the need the future improvement of the present approach by supporting bacterial vinyl-chloride oxidation, to achieve a complete degradation of chloroethenes.
microbial bioremediation; organohalide respiration; permeable reactive bio-barrier; microcosms; reductive dehalogenases; Chloroflexi
Settore AGR/16 - Microbiologia Agraria
5-set-2021
Article (author)
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/2434/864427
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